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Background

Epidemiology and transmission of diarrhoeal disease and soil-transmitted helminth infection

Despite advances in prevention and treatment, diarrhoea and soil-transmitted helminth (STH) infections still represent a large disease burden, particularly in low-income countries. Diarrhoeal diseases account for an estimated 1.4 million deaths worldwide and rank fourth globally for leading causes of years of life lost due to premature mortality (Lozano 2013). Among children under the age of five, diarrhoea kills more than 700,000 children annually, making it the second leading cause of mortality after pneumonia (Walker 2013). Over five billion people worldwide, including one billion school-aged children (aged five to 14 years), are at risk of infection with at least one STH species (Pullan 2012). The three STHs responsible for most infections are Ascaris lumbricoides, Trichuris trichiura and hookworms (Ancylostoma duodenale or Necator americanus), with 819 million, 464.6 million and 438.9 million people infected in 2010 respectively (Pullan 2014).

The pathogens that cause diarrhoea are mainly transmitted via the faecal-oral route (Byers 2001). Pathogens from contaminated faeces can be passed on to a new susceptible host via contaminated hands, drinking water, soil, flies, or by ingesting contaminated food (Wagner 1958). The settings, pathogens and their prevalence in different populations will determine the importance of each transmission route (Brown 2013). The symptoms of diarrhoea and course of disease vary with age, nutritional and immune status of the infected person, and the causative pathogens (Clasen 2010). The main characteristics of infection are changes in stool consistency, increases in volume or fluidity, and increased frequency of defecation (Thapar 2004). The three clinical presentations of diarrhoea are: (1) acute watery diarrhoea lasting several hours or days, (2) acute bloody diarrhoea (dysentery) and (3) persistent diarrhoea lasting 14 days or more (Heymann 2008). The direct threat from acute watery diarrhoea is dehydration, loss of fluids and electrolytes. Severe dehydration can result in death if untreated (Keusch 2006).

STHs are transmitted via ingestion of STH eggs (A. lumbricoides and T. trichiura) or larvae (A. duodenale), or via penetration of third stage larvae (hookworms) (Bethony 2006). The larvae go through several developmental stages in the human host and depending on the species, the adult parasites can settle in different parts of the gastrointestinal (GI) tract, where they can live several years, mating and producing eggs that are passed in the faeces (Bethony 2006). The eggs (A. lumbricoides and T. trichiura) and larvae (hookworm) can survive in the soil for several months or several weeks, respectively, depending on the environmental conditions, including humidity, soil moisture and temperature (Brooker 2006). Morbidity caused by STHs is linked to the intensity of infection, which is the number of worms per human host measured by the number of eggs per gram of faeces (Bethony 2006). STHs infections can have several clinical features, which can be classified into acute manifestations linked to larval migrations through the skin and intestines, and acute and chronic manifestations associated with parasite presence in the GI tract (Bethony 2006).

In addition to the direct health consequences of diarrhoeal diseases and STHs infections, they have longer term impacts on human development due to malabsorption and malnutrition (resulting in stunting and chronic anaemia), and on capacity (via lower cognition, school absenteeism and inability to work); which in turn can have impacts on development and poverty (Harhay 2010). STHs are believed to be one of the main causes of physical and intellectual growth retardation in the world (Bethony 2006).

Sanitation and disposal of child faeces

As the aetiological agents associated with diarrhoea and STHs are transmitted through faeces, the safe collection and disposal of human excreta has the potential to significantly reduce exposure and disease. When readers of the British Medical Journal were asked to vote on the "greatest medical advance" since 1840, they chose the sanitary revolution (the introduction of clean water and sewage disposal) over antibiotics, anaesthesia, vaccines and germ theory (Ferriman 2007). Large scale efforts have been made to increase coverage of improved sanitation, most recently as part of the Millennium Development Goal (MDG) sanitation target of halving the proportion of the population without access to basic sanitation by 2015 (United Nations 2013). However, this target is far from being met; 2.5 billion people were still without improved sanitation by the end of 2011 including more than one billion people who were practicing open defecation (WHO/UNICEF 2013).

A series of published systematic reviews have consistently concluded that sanitation interventions are effective in preventing diarrhoea and STH infections. Esrey 1991 reported a 22% median reduction in diarrhoea from 11 observational studies and 36% from the five rigorous studies. They also reported reduction in Ascaris and hookworm from water supply and sanitation interventions, especially on the reduction in disease intensity (egg counts). Fewtrell 2005 reported a pooled estimate risk on diarrhoea of 0.68 (95% confidence interval (CI) 0.53 to 0.87) from two intervention studies. Waddington 2009 reported a pooled estimate of 0.63 (95% CI 0.43 to 0.93) from six controlled studies among children. Clasen 2010 found a consistent protective effect against diarrhoea among 13 intervention studies but noted that nearly all involved water or hygiene interventions in addition to sanitation. Norman 2010 reported that sewerage led to a 30% reduction in diarrhoea (RR 0.70, 95% CI 0.58 to 0.85) among 17 observational studies. Ziegelbauer 2012 reported that sanitation interventions were protective against Ascaris, Trichuris and hookworm.

All of these reviews, however, focused on interventions to improve coverage, use or functionality of sanitation facilities; none specifically addressed the disposal of child faeces, another source of exposure even among households with improved sanitation. Actually, the unsafe disposal of child faeces may represent a more significant health risk than that of adults. This is because young children have the highest incidence of enteric infections (Walker 2012), and their faeces are most likely to contain infectious agents (Feachem 1983). Young children are more likely to defecate in places where susceptible children could be exposed (Lanata 1998). This exposure is worse for other young children due to the amount of time they spend on the ground and their exploratory behaviours including putting fingers and fomites in their mouths, and common behaviours such as geophagia (intentional consumption of earth) (Moya 2004; Ngure 2013; Young 2011). Perhaps for these reasons, World Health Organization (WHO) and United Nations Children’s Fund (UNICEF) Joint Monitoring Programme for Water Supply and Sanitation (JMP), which is charged with assessing progress toward the MDG sanitation target, treats disposal of child faeces that are not deposited in a latrine or buried as unsanitary (WHO/UNICEF 2006).

An additional risk of contamination of the environment with faeces, including those of children, is that it may result in extended exposure of children to faecal pathogens which may lead to enteropathy, a disorder of the small intestine that is characterised by villous atrophy, crypt hyperplasia, inflammatory cell infiltrate, increased permeability and malabsorption (Humphrey 2009). Enteropathy is thought to lead to under nutrition and growth faltering (Humphrey 2009; Lin 2013).

We are unaware of any published, peer-reviewed study summarizing the evidence on the impact of child faeces disposal on human health. In an unpublished review and meta-analysis of 10 observational studies published between 1987 and 2001, Gil 2004 found that child faeces disposal behaviours considered risky (open defecation, stool disposal in the open, stools not removed from soil, stools seen in household soil and children seen eating faeces) were associated with a 23% increase in risk of diarrhoeal diseases (RR 1.23, 95% CI 1.15 to 1.32); on the other hand, behaviours considered safe (use of latrines, nappies, potties, toilets, washing diapers) were borderline protective (RR 0.93, 95% CI 0.86 to 1.00). In a study in rural Bangladesh, it was found that the disposal of child faeces in closed spaces such as pit latrines resulted in a 35% reduction in helminthiasis in children under two compared with disposal in open space (Roy 2011) indicating that safe disposal of child faeces may also play a role in the control of STH infections.

Objectives

To assess the effectiveness of interventions to improve the disposal of child faeces for preventing diarrhoea and STH infections.

Methods

Criteria for considering studies for this review

Types of studies

We will include randomized controlled trials (RCTs) that are individually- or cluster-RCT and the following non-randomized controlled studies (NRS): quasi-RCTs, non-RCTs, controlled before-and-after studies, interrupted-time-series studies, historically controlled studies, case-control studies, cohort studies, and cross-sectional studies (see definitions in Appendix 1). We will include NRS as based on a previous review (Gil 2004) we assume that there will be no or very few RCTs assessing the effect of improved disposal of child faeces for preventing diarrhoea and STH infection. We will exclude non-controlled studies, such as case reports or case series, due to the importance of control groups to determine the effect of the intervention on the outcomes of interest.

Types of participants

Adults and children.

Types of interventions

Intervention:

All interventions aiming to improve the safe collection or disposal of faeces of children aged below five years in order to decrease direct or indirect human contact with such faeces. For NRS, we will include interventions that have occurred in the course of usual healthcare or daily life, or those that have been deliberately introduced. This will include, but not be limited to, safe disposal practices as defined by the JMP, namely direct defecation into a latrine, disposal of stools in a latrine, or burying of stools (WHO/UNICEF 2006). Interventions can include the provision of hardware (for example, nappies (diapers), potties, faecal collection devices, cleaning products to hygienically remove faeces, child-friendly squatting slabs or latrines used by children), software (for example, promotion of safe disposal practices), or both. We will include interventions that combine the safe disposal of child faeces with other interventions, such as hygiene promotion interventions, and employ subgroup analysis to investigate the impact of these additional interventions.

Control:

Participants that continue their usual practices of child faeces disposal instead of the intervention, or who received a different type of intervention (for example, a heath promotion intervention).

Types of outcome measures

Primary outcomes

Diarrhoea episodes among individuals, whether or not confirmed by microbiological examination.

We will define an episode according to the case definitions used in each reviewed study. This includes the WHO definition, which is the passage of three or more loose or liquid stools per day or more than usual for the individual (WHO 2013). We will treat this outcome as dichotomous; whether an individual has had one or more episodes of diarrhoea.

Infection with one or more species of STHs (Ascaris lumbricoides, Trichuris trichiura,Ancylostoma duodenale orNecator americanus). We will define infection as the presence of eggs, or juvenile nematodes, or both in the stools of the participants. We will include any accepted diagnostic techniques.

Secondary outcomes

Dysentery

Severe diarrhoea

Persistent diarrhoea

Clinical visits for diarrhoea

Intensity of STH infection (number of eggs per gram of stool)

Presence of pathogenic microbes in stool assays

Anthropometry (weight-for-age and height-for-age)

Serology

Other markers of infection and disease

Mortality

Use and adoption of the intervention (behaviour change)

Adverse events

Search methods for identification of studies

We will attempt to identify all relevant studies regardless of language or publication status (published, unpublished, in press and ongoing).

Electronic searches

We will search the following databases using the search terms detailed in Appendix 2: CIDG Specialized Register; Cochrane Central Register of Controlled Trials (CENTRAL), published in The Cochrane Library; EMBASE; MEDLINE; Global Health; Web of Science; LILACS; and POPLINE. Also, we will examine Chinese-language databases available in the China National Knowledge Infrastructure and the Wan Fang Portal using the search terms detailed in Appendix 2 or their Chinese language equivalents. We will search the metaRegister of Controlled Trials (mRCT), clinicaltrials.gov and International Clinical Trials Registry Platform Search Portal (www.who.int/trialsearch) using "sanitation" and "hygiene" as search terms, as well as an index to theses in the United Kingdom (http://ethos.bl.uk). We will search Open Grey (http://www.opengrey.eu) database for grey literature.

Searching other resources

Conference proceedings

We will search the following organizations' conference proceedings: International Water Association and Water, Engineering and Development Centre, Loughborough University, UK.

Researchers and organisations

We will contact individuals working in the field, and contact or search websites of the following organizations for other potential published and unpublished studies: Water, Sanitation and Health Programme of the WHO; World Bank Water and Sanitation Program; UNICEF Water, Environment and Sanitation; Environmental Health Project (USAID); IRC International Water and Sanitation Centre; Global Water, Sanitation and Hygiene (CDC); International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B); US Agency for International Development (USAID); UK Department for International Development (DFID); Asian Development Bank (ADB); WASHplus (http://www.washplus.org/); sustainable sanitation alliance (http://www.susana.org/); community-led total sanitation (CLTS); the sanitation updates blog (http://sanitationupdates.wordpress.com/); and the STEPS Centre at the Institute of Development Studies University of Sussex (http://steps-centre.org).

Reference lists

We will check the reference lists of studies identified by the above methods.

Data collection and analysis

Selection of studies

Fiona Majorin (FM) and Belen Torondel (BT) will independently examine titles and abstracts of all identified studies and select all potentially eligible studies based on the inclusion criteria. If a title or abstract cannot be rejected with certainty due to lack of information, we will obtain the full text of the article for further assessment. Gabrielle Ka Seen Chan (GC) will review the results of the Chinese database search, undertake the same process as FM and BT, and summarize the potentially eligible articles in English. We will obtain full copies of all studies agreed by either author to potentially fall within the inclusion criteria. FM and BT will independently determine whether each study meets the inclusion criteria using a form. We will check study reports to ensure that multiple publications of the same study are only included once. When we agree, we will either include or exclude the study. If we are unable to agree, we will consult Thomas Clasen (TC) who will make the final decision. FM will correspond with authors in case data needed to assess eligibility is not obvious in the study or if data is missing from the report. Any studies that FM or BT suggest to include but which are ultimately excluded through discussion or by TC will be presented with the reason for exclusion in the 'Characteristics of excluded studies'.

Data extraction and management

FM and BT will independently extract data from the included studies using a data extraction form after it has been piloted (items included in the form are presented in Appendix 3). In case of discrepancy, we will discuss the data and consult TC, if necessary, who will make the final decision. FM will enter and analyse the agreed data into Review Manager (RevMan) and BT will independently cross-check a sample of the data.

Type of data to be extracted

RCTs randomized by individual

For each RCT we will extract the number of participants randomized and the numbers analysed in each treatment group for each outcome. For dichotomous outcomes, we will extract the number of participants experiencing the outcome and the number of participants in each treatment group. For continuous outcomes, we will extract the means, standard deviations and number of participants in each group.

RCTs randomized by cluster

For cluster RCTs we will extract the number of participants randomized and the number analysed in each treatment group for each outcome. When the cluster RCT has been adjusted for clustering in the analysis, we will extract the measures of effect that have been adjusted for clustering and the CIs. When the cluster RCT has not adjusted for clustering in the analysis, we will extract measures of effect and CIs, as well as average cluster sizes and intra-cluster correlation coefficients (ICC) to approximate correct analysis that account for clustering using the inflating standard error method (Higgins 2011a).

NRS

For NRS, we will extract details on the features of the design, the confounding factors considered in the study, methods used to control for confounding, data on the risk of bias specific for NRS (see Assessment of risk of bias in included studies), the total numbers of participants included in the study and in each comparison group, the measures of effect and CIs.

Assessment of risk of bias in included studies

Two authors will independently apply the risk of bias criteria using an assessment form. In case of disagreement we will discuss the issue and if necessary consult a third author, TC, to make the final decision. If there's any missing data required to assess the risk of bias, FM will contact the authors for additional information. For each study, we will justify reasons for the level of risk of bias and include it in the 'Risk of bias' table.

For RCTs randomized by individuals and by cluster, we will use the Cochrane Collaboration tool (Higgins 2011b) to assess the risk of bias, which includes methods of random sequence generation, allocation concealment, blinding of participants, personnel and outcome assessment, incomplete outcome data and selective reporting. For each domain, we will follow the definitions of low risk, unclear risk and high risk described in Higgins 2011b.

For cluster RCTs we will also assess the risk of bias specific to this study design:

Recruitment bias. We will qualify the study as high risk of bias in case the participants and staff were aware of which cluster was the intervention or control; unclear risk in case the information was not collected or reported; or low risk of bias if clusters are not known to be intervention or control during participant recruitment.

Baseline imbalance. We will assess a study as high risk of bias when large differences in baseline characteristics were present and they were not adjusted for in the analysis; low risk of bias in case statistical methods are used to match the clusters at the design stage or to adjust for imbalances in the analysis, or in case no substantial differences in baseline characteristics are observed; or unclear risk if it is not mentioned in the report.

Loss of clusters. We will qualify studies as high in case > 10% of clusters are lost to follow-up; low risk of bias if < 10% of clusters are lost to follow-up; or unclear if loss to follow-up is not mentioned.

Incorrect analyses. We will assess studies as high risk of bias if they did not analyse the data adjusting for clustering; low risk of bias in case there are no unit-of analysis errors in the study and if clustering is adjusted for in the analysis; or unclear risk if it's not reported in the study. We will calculate estimate corrections to adjust for clustering when analysing these high risk of bias studies.

Comparability with individually randomized RCTs. We will analyse cluster-RCTs separately to individually randomized RCTs as it is likely that community effects of improved child faeces disposal are observed in cluster RCTs.

We will use the EPOC criteria (EPOC 2013) to assess the risk of bias of the included quasi-RCTs, non-RCTs, controlled before-and-after studies, historically-controlled studies and controlled interrupted-time-series studies (ITS), controlled cohort and cross-sectional studies. For all study designs except ITS, this tool includes random sequence generation, allocation concealment, incomplete outcome data, selective outcome reporting and other biases that are similar to the RCT risk of bias tool, as well as the following additional domains:

Similarity of baseline characteristics. Important baseline characteristics for this study include: access and type of sanitation facilities, water access and quality, age, wealth and hygiene practices. We will qualify the studies as high in case there are substantial differences; low risk of bias if baseline characteristics are reported and there is no substantial difference; or unclear if it's not reported or unknown.

Similarity of baseline outcome measurements. We will give high risk of bias scores when large differences were present and they were not adjusted for in the analysis; low risk of bias scores to studies if participant outcomes were measured prior to the intervention and there were no substantial differences; or unclear risk if it is not mentioned in the report.

Adequate protection against contamination? We will qualify the study as high risk if it is likely that the control group received the intervention; low risk if it is unlikely that the control group received the intervention; or unclear in case it is possible contamination could have occurred.

Adequate allocation of intervention concealment during the study. We will classify studies as high risk if the outcomes were not assessed blindly; low risk of bias if the authors explicitly report that the primary outcomes were assessed blindly or the outcomes are objective; or unclear if it's not specified in the paper.

For ITS, the tool includes seven domains, for which we will use the definitions of high risk, low risk and unclear risk suggested by EPOC: intervention independent from other changes, pre-specified shape of the intervention, whether the intervention was likely to affect the data collection, whether knowledge of the allocated interventions was adequately prevented, incomplete outcome data, selective outcome reporting and other biases (EPOC 2013).

We will also add a domain to assess whether the studies appropriately adjusted for confounders. The following confounders related to child faeces disposal and diarrhoea or STHs infections are considered important for this review: access to or ownership of a sanitation facility, type of sanitation facility (improved or unimproved according to the JMP classification (WHO/UNICEF 2014), use of sanitation facility, wealth, age, water access, season, water quality, animal ownership, household size, educational level, attendance to school or pre-school by the children, shoe-wearing and hygiene practices. We will classify studies as low risk if they control for at least one of the listed confounders in the design (for example, matching) or the analysis (for example, multivariable statistical modelling). We will classify studies as high risk if no adjustment for confounding variables is conducted and unclear in case it is not mentioned in the paper.

For case-control studies we will assess the quality of the studies using the Newcastle Ottawa scale (NOS) (Wells 2013). The scale is divided into eight items grouped into three domains: selection, comparability and ascertainment of exposure. For each item in the selection and exposure ascertainment domains a total of one 'star' can be awarded to a study; in the comparability domain two stars can be awarded. For one star in the comparability domain, the study will control for access to or ownership of a sanitation facility. For two stars, the study will have to control for at least one other important confounding variable, such as type of sanitation facility (improved or unimproved) use of sanitation facility, wealth, age, water access, season, water quality, animal ownership, household size, educational level, attendance to school or pre-school by the children, shoe-wearing and hygiene practices.

Measures of treatment effect

For RCTs with dichotomous outcomes, we will calculate the risk ratios (RR) with 95% CIs in case the raw data are available. If not we will use the effect measures reported including rate ratios or risk ratios, along with the 95% CI. For continuous variables, we will extract the mean differences or the standardized mean difference (SMD) in case different studies use different measures. We will calculate or extract standard errors and 95% CI from these studies.

For NRS studies, we will report measures of effect adjusted for confounders from the studies. If several adjusted estimates are reported, we will use the estimate adjusting for the most confounders. We will specify the confounders that were adjusted for in the study and how that was done whether it was in the design or in the analysis. In case the effect measures extracted are expressed in different metrics, we will convert them into a common measure, RR, to pool them if possible; if they are all the same, we will combine them using the effect measure used in the reports. If no adjusted measures can be obtained from the studies, we will use unadjusted measures reported in the study or calculate RR and 95% CI from the raw data.

Unit of analysis issues

We will consider individually RCTs and cluster-RCTs. For the latter, we will assess whether clustering was properly accounted for in the analysis and use the adjusted measure of effect reported. We will analyse cluster-RCTs and individually RCTs separately.

Dealing with missing data

If studies have missing data needed for assessment of eligibility or analysis, FM will contact authors and attempt to obtain the data. We will report on the number of participants in each study and the number of participants that were lost to follow-up.

Assessment of heterogeneity

We will assess heterogeneity by visually examining the CIs in the forest plot and by using the Chi2 test and I2 statistic (Higgins 2003). We will consider a significance level of < 0.1 for Chi2 test to be significant and indicate potential heterogeneity. To estimate the degree of heterogeneity, we will classify an estimate of I2 > 50% to indicate substantial heterogeneity and > 75% to indicate considerable heterogeneity (Deeks 2011). If there are sufficient studies (> 10) and substantial heterogeneity, we will investigate causes of heterogeneity using subgroup analysis and meta-regression where appropriate, specifically to investigate the effects of the study designs, study quality and types of intervention.

Assessment of reporting biases

We will try to minimise reporting bias by using a comprehensive search strategy including published and unpublished studies. If study protocols are available, we will compare the study protocol with the published results to check if all planned outcomes are reported on. If not, we will compare the outcomes listed in the methods and those reported in the results sections. We will assess the potential of publication bias using funnel plots in case we find sufficient studies (> 10) and they are of different sizes.

Data synthesis

We will analyse the data using Review Manager (RevMan). If there is more than one study with comparable participants, interventions and outcomes, and there isn't considerable heterogeneity between the studies (I2 statistic value > 75%) we will conduct a meta-analysis to estimate a pooled measure of effect. We will use a random-effects model to pool the data. The comparisons made will be between those with the intervention and those without or with a different intervention. Due to differences in potential risk of bias of different study designs (Reeves 2011), we will only pool results of similar study designs.

In case the studies included have varying degrees of risk of bias, we will conduct stratified analysis according to the level of risk of bias of the studies.

If there are not enough similar studies to pool them together, we will show the individual study results on the forest plot without displaying a pooled estimate and we will conduct a systematic description of the results. The studies will be organized by type of intervention and study design when described.

Summary of findings table

Two review authors (BT and FM) will assess the methodological quality of each outcome across the included studies using GRADE guidelines (Guyatt 2011). In case of discrepancy, a third author (TC) will assess the methodological quality. We will summarize the 'Summary of findings' table using GRADEpro.

The following outcomes will be presented in the 'Summary of findings' table:

Diarrhoea episodes;

Infections with one or more species of STHs.

Subgroup analysis and investigation of heterogeneity

We will conduct meta-analyses of studies with comparable participants, interventions and outcomes such as:

The effects of different types of interventions, such as software versus hardware, collection versus disposal, burying faeces versus disposal or defecation in a latrine, use of different faeces collection tools such as potties versus diapers;

The effects of single versus combined interventions (for example, in combination with improved water supply, hygiene, or improved sanitation).

Then, within each of these meta-analyses, if there are sufficient comparisons (> 10) included in the review, we will conduct subgroup analyses to investigate:

The effects of different methods to ascertain use of the intervention (for example, observations versus survey questionnaire reporting on child faeces disposal method);

The effects of different levels of baseline/end line coverage and compliance with the intervention;

The effects of different study designs;

The effects of the intervention site (urban versus rural);

The effects of the intervention settings (low, middle or high income country);

The effect of safe child faeces disposal on infections with different STHs species (for example, A. lumbricoides versus hookworms);

The effect of safe child faeces disposal on outcomes in different age groups, children aged < 5 years versus children aged > 5 years.

Sensitivity analysis

We will conduct sensitivity analyses in case there are disagreements with eligibility criteria and to check robustness of the choice of analysis method (random-effects model versus fixed-effect). If there are sufficient studies, we will perform sensitivity analyses comparing inclusion of studies with different methodological quality. Where there are other debated decisions during the review process, we will conduct other sensitivity analyses investigating these issues when possible.

Acknowledgements

The editorial base for the Cochrane Infectious Diseases Group is funded by the UK Department for International Development (DFID) for the benefit of developing countries.

Appendices

Quasi-RCT: A study with an experimental design where participants are allocated to different interventions using a quasi-random method, such as date of birth, alternation, and medical record number.

Non-RCT: A study with an experimental design where participants are allocated to different interventions using a non-random method.

Controlled before-and-after study: A study where observations are made in a control and intervention group, before and after the implementation of an intervention.

Interrupted-time-series study: A study in which observations are done at multiple time points before and after an intervention (interruption). The design of the study enables to see if the intervention has an effect that is significantly greater than underlying trend over time.

Historically controlled study: A study comparing a group of participants receiving an intervention with a similar group from the past that didn't.

Cohort study: A study that follows a defined group of people (cohort) over a period of time to examine interventions received and subsequent outcomes. A 'prospective' cohort study recruits participants before an intervention and follows them whereas a 'retrospective' cohort study recruits participants from the past using records from the past that describe the interventions received and follows them in the past using the records.

Case-control study: A study that compares participants with a certain outcome (cases) with people from the same source population without the outcome (controls) and examines the associations between the outcome and prior exposures (for example, receiving an intervention).

Cross-sectional study: A study where information on past or current interventions and health outcomes are collected for a group of people at a particular time point in order to study associations between outcomes and exposure to interventions.

Appendix 2. Detailed search strategy

Search set

CIDG SR1

CENTRAL

MEDLINE

EMBASE

Global Health

Web of Science

LILACS

POPLINE

1

feces OR faeces OR faecal OR fecal OR stool* OR excreta* OR excrement OR diarrhoea OR diarrhea OR defeacation OR defecation OR human waste

feces OR faeces OR faecal OR fecal OR stool* OR excreta* OR excrement OR diarrhoea OR diarrhea OR defeacation OR defecation OR human waste

(f?eces or f?ecal or stool$ or excreta$ or excrement or diarrh?ea or defe?cation or human waste) adj3 (management or dispos$ or remov$ or cleansing or cleaning or washing))

(f?eces or f?ecal or stool$ or excreta$ or excrement or diarrh?ea or defe?cation or human waste) adj3 (management or dispos$ or remov$ or cleansing or cleaning or washing))

(f?eces or f?ecal or stool* or excreta* or excrement or diarrh?ea or defe?cation or human waste) adj3 (management or dispos*or remov* or cleansing or cleaning or washing))

F$eces OR f$ecal OR stool* OR excreta* OR excrement OR diarrh$ea OR defe$cation OR human waste

feces or faeces or fecal or faecal or stool$ or excreta$ or excrement or diarrhea or diarrhoea or defecation or defeacation or human waste

feces OR faeces OR faecal OR fecal OR stool* OR excreta* OR excrement OR diarrhea OR diarrhoea OR defeacation OR defecation OR human waste

2

management OR dispos*OR remov* OR cleansing OR cleaning OR washing

management OR dispos*OR remov* OR cleansing OR cleaning OR washing

sanitation or potty or potties or diaper$ or nappy or nappies or latrine$ or toilet$ or cloth$ diaper$ or swaddle or wrap$

sanitation or potty or potties or diaper$ or nappy or nappies or latrine$ or toilet$ or cloth$ diaper$ or swaddle or wrap$

sanitation or potty or potties or diaper* or nappy or nappies or latrine* or toilet* or cloth* or diaper* or swaddle or wrap*

management OR dispos*OR remov* OR cleansing OR cleaning OR washing

management or dispos$ or remov$ or cleansing or cleaning or washing

management OR dispos* OR remov* OR cleansing OR cleaning OR washing

3

1 AND 2

1 AND 2

1 or 2

1 or 2

1 or 2

1 AND 2

1 AND 2

1 AND 2

4

sanitation OR potty OR potties OR diaper* OR nappy OR nappies OR latrine* OR toilet* OR cloth* OR diaper* OR swaddle OR wrap*

sanitation OR potty OR potties OR diaper* OR nappy OR nappies OR latrine* OR toilet* OR cloth* OR diaper* OR swaddle OR wrap*

exp Sanitation/

exp sanitation/ or exp environmental sanitation/

exp sanitation/

sanitation OR potty OR potties OR diaper* OR nappy OR nappies OR latrine* OR toilet* OR cloth OR diaper* OR swaddle OR wrap*

child$ or babies or baby or infant$ or toddler$ or neonate$ or preschool or pre-school

sanitation OR potty OR potties OR diaper* OR nappy OR nappies OR latrine* OR toilet* OR cloth OR diaper* OR swaddle OR wrap*

5

3 OR 4

3 OR 4

3 or 4

3 or 4

3 or 4

3 OR 4

3 AND 4

3 OR 4

6

child* OR babies OR baby OR infant* OR toddler* OR neonate* OR preschool OR pre-school

[Sanitation]

child$ or babies or baby or infant$ or toddler$ or neonate$ or pre?school

child$ or babies or baby or infant$ or toddler$ or neonate$ or pre?school

child* or babies or baby or infant* or toddler* or neonate* or pre?school

child* OR babies OR baby OR infant* OR toddler* OR neonate* OR preschool OR pre$school

Keywords : sanitation OR Hygiene

7

5 and 6

5 OR 6

exp child/ or exp child, preschool/ or exp infant/

exp child/

exp children/

5 AND 6

5 OR 6

8

child* OR babies OR baby OR infant* OR toddler* OR neonate* OR preschool OR pre-school

6 or 7

6 or 7

Exp infants/

child* OR babies OR baby OR infant* OR toddler* OR neonate* OR preschool OR pre-school

Type of outcome: diarrhoea episodes; infections with one or more species of STHs; intensity of infection with one or more species of STH; dysentery; severe diarrhoea; persistent diarrhoea; clinical visits for diarrhoea; presence of pathogenic microbes in stools; anthropometry; serology; other markers of infection and disease; adverse events; mortality; or behaviour change?

If excluded, reasons for exclusion:

Characteristics of included studies

Country and district, state, or town

Setting (hospital, school, community, urban, or rural)

Season

Design

Description of design

Was it a multicentre study?

Funding source

Duration of study (start and end date of study)

Duration of participation (start of recruitment until last follow-up time point)

Ethical approval if needed

Missing data and reasons

Unit of randomization and whether the analysis adjusted for clustering if cluster design

Participants:

Population demographics

Study inclusion criteria

Study exclusion criteria

Method of participant recruitment

Total number of participants recruited

Withdrawals, exclusions, loss to follow-up

Age

Sex

Household size

Education level

Socio-economic level

Pre- and post-intervention water quality

Sanitation type and coverage

Hygiene practices

Type of water supply and coverage

Baseline child faeces disposal sites

Prevalence of open defecation

Deworming history in the study population

Solid waste disposal practices

Animal ownership

School or pre-school attendance

Shoe wearing practices

Intervention group

Description of intervention

Number of participants

Co-interventions?

Who delivered the intervention?

Format and timing of delivery?

Coverage and uptake of child faeces collection and disposal practices

Compliance to intervention

Control group

Description of control

Number of participants

Co-intervention?

Outcomes

Case definition for health outcomes

Measuring/diagnosis method (if self-reported include recall period)

Time points measured

Effect estimate and 95% CI and raw numbers (for NRS record adjusted and unadjusted measures with confounders adjusted for; for cluster RCT specify if effect estimate is adjusted for clustering)

Moya 2004

Ngure 2013

Ngure FM, Humphrey JH, Mbuya MN, Majo F, Mutasa K, Govha M, et al. Formative research on hygiene behaviors and geophagy among infants and young children and implications of exposure to fecal bacteria. American Journal of Tropical Medicine and Hygiene2013;89(4):709-16.

WHO 2013

WHO/UNICEF 2006

World Health Organization, United Nations Childrens' Fund. Core questions on drinking water and sanitation for household surveys. http://www.who.int/water_sanitation_health/monitoring/oms_brochure_core_questionsfinal24608.pdf. Geneva: World Health Organization, (accessed on 13 March 2014).

WHO/UNICEF 2013

World Health Organization, United Nations Childrens’ Fund. Joint Monitoring Programme for Water Supply and Sanitation. Progress on sanitation and drinking water: 2013 Update. http://apps.who.int/iris/bitstream/10665/81245/1/9789241505390_eng.pdf. World Health Organization and United Nations Children’s Fund., (accessed on 12 March 2014):1-40.